CRX Road to Racing – Part 8 : Fuel Cell Turnabout

March 26, 2014

CRX Road to Racing – Part 8 : Fuel Cell Turnabout

With driving season over, it was time to work on making the CRX Road Race worthy. There are various safety requirements I needed to meet in order to run on the track. One of the biggest issues was the fuel cell. We had to replace the aluminum can with a proper, safe fuel cell.

First, we removed the old fuel "cell" which wasn’t much more than an aluminum box with some fittings welded to it. The cell was held in with 1" thick steel straps bolted through the car's sub frame. Not the safest thing ever. After putting the old cell on craigslist, it didn't take long to sell it. I even gave the new owner a fuel level gauge and an extra sending unit for the cell.

We ordered a new 12 gallon ATL fuel cell, and, after a couple damaged shipments, we got started. First we measured things and made sure the cell would fit in the car in a safe location, which meant sitting higher than the lowest parts of the car. We constructed a cage that fit around the cell and allowed the cell to be bolted in place. We welded the cage together and mounted it in the car.

The fuel cell barely fit between the mounting cage and the roll cage sideways, then it could be rotated and lowered into place. We drilled and tapped holes in the mounting cage so the fuel cell would bolt in place using its existing hardware and torqued all of the hardware down.

The next step to meet safety rules was to cover the fuel cell with a bulkhead so if there was a fire it wouldn't enter the passenger compartment. The bulkhead would need a removable panel so we could fill the fuel cell up easily. A lot of time was spent trying to match the floor board to the panels caulking was used to close small gaps between the uneven floor and the cell. We ended up making 2 lids because the thinner aluminum flexed too much and wouldn't seal. We then mounted some quarter turn fasteners and sealed the lid up.

Finally, we got to mounting and plumbing the existing fuel system into the bulkhead area. Utilizing the bulkhead's support rails, I mounted the pump and the filter was mounted in turn to the fuel cell mounting cage. For the vent line we decided to use the FATS (Fuel Air Trap System) method of keeping fuel from escaping in addition to the check valve (which keeps fuel from pouring out if the car is on its roof). The FATS involves running the hose uphill past one side of the cell and returning uphill past the other side then terminating the line below the bottom of the cell. This keeps fuel from being able to drain in any direction and, if fuel ends up in the hose, in theory it should drain back into the cell.  

 

  That is all for this issue of CRX Road to Racing. Check back soon!




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